Coherent superposition of emitted and resonantly scattered photons from a two-level system driven by an even-$\pi$ pulse

TL;DR

This paper demonstrates the coherent superposition of emitted and resonantly scattered photons from a two-level quantum dot system driven by even-$\pi$ pulses, revealing a photon bunching phenomenon with potential quantum technology applications.

Contribution

It reports the experimental observation of a superposition state involving emitted and scattered photons in a two-level system driven by specific laser pulses, a novel quantum optical effect.

Findings

Observation of photon bunching (~3 photons) due to superposition

Polarization change of scattered photons by the resonant system

Potential for high-order Fock state generation in quantum technologies

Abstract

We report the observation of a bunching of ~3 photon states, which is a coherent superposition of emitted photons and resonantly scattered laser photons, arising upon excitation by even-$\pi$ pulses of a two-level system represented by a charged quantum dot in a microcavity. This phenomenon emerges because the exciting laser pulse contains several tens of photons whose quantum amplitude distribution creates such a superposition, and the polarization of the scattered photons is changed by the interaction with the charged resonant system. Such a beam is a high-order member of the Fock space, promising for quantum technologies.